Development of smart heat interface units and demonstration of networked, highly efficient, regenerative heat supply for Multi-Family Houses, WoSta4.0

Introduction

The heat demand for domestic hot water (DHW) in the building sector has remained almost constant in recent years, while the heat demand for space heating (SH) has been reduced further and further due to the ambitious building regulations of building structure (e.g. insulation). DHW-preparation is thus becoming increasingly important for the energy policy in Germany. The typical temperature level of the domestic hot water of 55 to 60 °C required for hygienic reasons (with central DHW systems) can hardly be reduced and makes the use of “low-temperature systems” or “Low-Ex systems” more difficult. These “low-temperature systems” tend to use the low temperature level of renewable energies and avoid destruction of exergy. In apartment buildings or so-called Multi-Family Houses, central fresh water stations (central instantaneous potable water heaters) have so far been able to slightly reduce the temperature level in the heating centrals (Pärisch 2020). Decentralized heat supply concepts with heat interface unit (decentralized instantaneous potable water heaters) are a promising approach of providing domestic hot water in Multi-Family Houses with a minimal risk of pathogenic microorganisms, without the need for circulation (if the “3-liter rule” is observed) and with a temperature level of less than 50 °C (Weiland et al 2021).

Project goals

The digitalization set as a part of the 7th energy research program in Germany and should lead to a smart and efficient building energy supply. In WoSta4.0, heat interface units are to be optimized through digital networking and intelligent control. The heat interface units in a multi-family house, which have so far been operated separately from each other in terms of static controlling and information technology, are to collect data on heat requirements (from users) and heat generation (form central heating units) through digital networking and lead to highly efficient energy supply through intelligent electronic controls. Digital networking can be implemented either through smartphone apps, operating devices or smart home stations. The demand-based intelligent control will use the space heating elements, the hydraulics, the operation temperature level and/or the heat generator. The resulting transparency of the decentralized energy supply in the apartments made possible by the smart heat interface units should lead to sufficient behavior on the part of the users (tenants), to the sensible use of resources in the heat supply and to new rental models such as fixed-, inclusive or flat-rate rents.

Project phases

Together with industry and district partners, the heat interface units of three German manufacturers will be tested, evaluated and optimized. In the first phase, the heat interface units are installed in the laboratory and coupled with domestic hot water tapping and heat load profiles that are dynamically emulated by building simulations. The heat interface units are subject to intensive laboratory tests to evaluate and characterize the intelligent control to be developed. In the second phase, the smart home stations in several houses of the district partners will be instrumented with the necessary control and measurement concepts in a manufacturer-specific manner and continuously updated with the results of the first phase. The home stations installed in the field are evaluated together and compared with 7 reference objects. Numerous controls, heat supply concepts and boundary conditions are examined in the third project phase with simulation programs in order to generalize the results of the first and second phases through parameter studies and to make them available to planners through knowledge transfer as design recommendations for the innovative smart heat interface units.

References:

Pärisch, Peter (2020): Parameter study of four different instantaneous water heaters in a solar assisted multi-family-house with TRNSYS. In: Alexandros Charalambides, Wolfgang Streicher und Daniel Mugnier (Hg.): Proceedings of the ISES EuroSun 2020 Conference – 13th International Conference on Solar Energy for Buildings and Industry. EuroSun 2020. Online, 9/1/2020 – 9/3/2020. Freiburg, Germany: International Solar Energy Society, S. 1–11.

Weiland, Finn; Büttner, Christoph; Schneider, Elisabeth; Pärisch, Peter (2021): Einfluss von Wärmeversorgungskonzepten mit Wohnungsstationen auf die Effizienz von erdgekoppelten Wärmepumpen-Systemen in Mehrfamilienhäusern. In: Energie und Umweltzentrum am Deister GmbH (e.u.[z.]). (Hg.): EffizienzTagung Bauen + Modernisieren. (2021). am 5. und 6. November 2021 (online). EffizienzTagung Bauen + Modernisieren.